Grounding of electrical systems is a practice which accomplishes multiple functions. Foremost among these functions is protection from shock hazard due to lightning, power surges, ground faults and inadvertent contact with high voltage lines. To prevent personal injury due to such electrical hazards, it has long been known in the electrical field to use low resistance ground connections to earth.
However, with the advent and widespread use of highly sensitive computer components, grounding has also been found to be necessary for the reliable operation of such components. Typically, computers and other advanced data processing equipment are located and operated in a dedicated room or area in a commercial building. These rooms are usually well air-conditioned to prevent over-heating of the equipment and, consequently, these rooms have a low-humidity level. Computer operators and other personnel working in these areas can create a build-up of static electricity in their body as a result of movement in this dry environment. Subsequent contact with static sensitive computer equipment can dissipate this static charge through the equipment, impeding its operating reliability and performance. Therefore, static shielding of computer equipment is highly desirable. Further, the signal frequencies of high speed computers reach and exceed 10 megahertz. The radiation of these high frequencies can also be troublesome to computer operation. Accordingly, shielding of computer circuits from such signal “noise” is also advantageous.
One method currently practiced for providing signal and static grounding uses a signal reference grid beneath the floor supporting the computer equipment. The signal reference grid, which is typically run beneath a raised floor, is electrically connected along its length to the various computer components and at one end to earth, either directly or indirectly. This provides adequate signal grounding to reduce signal “noise” radiated at high frequencies. The signal reference grid is also useful in providing static protection for the computer hardware. The raised flooring in a computer area is typically formed of a semi-conductive material, and is supported on modular floor supports made of steel or aluminum. It is desirous to electrically connect the floor supports to the signal reference grid so that the floor and the computer terminals are at the same electrical potential. A computer operator standing on the semi-conductive floor will then be at the same electrical potential as the computer terminal, eliminating any chances of static dissipation between the operator and the terminal.
The art has seen various types of grounding connectors and other devices which connect one cable to another. Examples of these are shown in U.S. Pat. No. 1,276,228 to Keenan et al. and U.S. Pat. No. 2,786,192 to Woolley, Jr. The grounding clamps that are currently in use attach single grounds and multiple grounds to the grounding clamp in a variety of different ways. Typically, these grounding clamps consist of a holding device for receiving the wire and a tightening bolt to secure it in place. Some styles of grounding clamps require special tools for assembly and installation, which can only be purchased from the manufacturer. Grounding clamps with multiple branches for connecting a plurality of grounding wires are always preferable over a single unit. However, many of the grounding clamps currently available can only be used with a limited range of wire sizes, for example 4 to 8 AWG. Also, many of the grounding clamps currently available can only be used with grounding posts within a limited range of sizes. For example, these grounding clamps can be used with a ⅞-inch or 1-inch grounding post, but cannot be used with a ½-inch or 1½-inch grounding post. Accordingly, there is a need for a grounding clamp that can be used to connect multiple wires of different sizes and that can be used with grounding posts that have a wide range of sizes.